<!DOCTYPE html>
<html lang="zh">

<head>
  <meta charset="UTF-8">
  <title>float 布局</title>
  <style>
    .box {
      width: 100px;
      height: 100px;
      background-color: lightblue;
      float: left;
      margin: 10px;
    }

    .clearfix::after {
      content: "";
      display: block;
      clear: both;
    }

    .continer {
      background-color: lightcoral;
      width: 100px;
      height: 100px;
    }
  </style>
</head>

<body>
  <div class="clearfix">
    <div class="box"></div>
    <div class="box"></div>
    <div class="box"></div>
  </div>
  <div class="continer">
    hello
  </div>
</body>

</html>